Although not exclusively, the present invention more particularly concerns aeronautical construction applications and also the construction of helicopters.
The production of helicopters is a complex operation implementing elaborated techniques and is subject to extremely strict production norms. These norms are imposed by two essential requirements:
the safety of the product in use, PA1 the guarantee of an equal production quality throughout the lifetime of the product so as to ensure: PA1 the data relating to the equation of said reference surface is stored in memory means; PA1 with the aid of optical sighting means, data are determined making it possible to calculate the equation characterizing said rough surface; PA1 the data relating to the equations of said reference surface and said rough surface are compared in an information processing unit; PA1 a mobile machining device is positioned close to said rough surface, and PA1 with the aid of said machining device controlled by specific orders according to said comparison and provided by said information processing unit, said rough surface is corrected so as to make the plane of the latter progressively coincide with that of said reference surface. PA1 memory means to store the data relating to the spatial equation characterizing said reference surface; PA1 optical sighting means to determine data making it possible to calculate the spatial equation characteristic of said rough surface; PA1 a mobile machining device able to be mounted and move on a girder of the frame close to said rough surface, and PA1 an information processing unit able to compare the data relating to firstly the equation of said reference surface, and secondly to the equation of said rough surface, and, on the basis of this comparison, to provide orders to said machining device controlled in such a way as to make the plane of said rough surface coincide with the plane of said reference surface.
firstly, the assembling during production without any finishing operation of the various elements constituting the product, PA2 and secondly after production, providing customers with standard spare parts.
Thus, the assembling of the elements constituting the structure of a helicopter, for example, needs to satisfy interchangeability requirements. So as to ensure this interchangeability, the elements to be assembled are kept in place on frames with the aid of braces secured to areas, that is, steel parallelepipedic plates sealed to the frame.
Generally speaking, the assembling frames are embodied from relatively light tubes having a square section, but with a large amount of inertia. They may be assembled by arc welding followed by stress-free annealing. Thus, frames are obtained having considerable rigidity on bending and torsion, but which are inexpensive and simple to produce. Once the frame has been produced, it is brought to its implantation site and finally cemented to the ground. The need to provide the areas for bracing the helicopter elements being assembled which were mentioned earlier is explained by the fact that the rough welded faces of the frame are not sufficiently precise to use as a base for fixing to the various braces. The areas are sealed to the frame girders by gluing them with resin or a similar substance, which allows a backlash of the gaps between the areas to be permitted by the resin thickness allowable for glueing. In fact, up until now, the adjustment of the frames has been accomplished by placing templates and standards on said frames. These areas are sealed and the braces used to support the elements to be assembled are secured to the areas of the frames.
These templates and standards are required for the production of new frames and the periodic checking of operational frames.
This involves producing a large number of templates and standards taking up a large amount of space and requires a costly complicated management of these tools for the periodic control of frames.
Thus, it would be desirable to avoid having to use these templates and standards. However, this brings up a new problem to the extent that the bracing areas would thus no longer be kept in place by rigid templates, thus rendering totally ineffective the method used up until now, that is of glueing the areas to the girders of the frame.